Simulations of time travel send quantum metrology back to the future
Unnati Akhouri
Physics WorldHave you ever wished you could go back in time and change your decisions? If only knowledge from today could travel back in time with us, we could alter our actions to our advantage. For now, such time travel is the stuff of fiction, but a trio of researchers have shown that by manipulating quantum entanglement, one can, at least, design experiments that simulate it.
Writing in Physical Review Letters, David Arvidsson-Shukur of the Hitachi Cambridge Laboratory, UK; Aidan McConnell of the University of Cambridge, UK; and Nicole Yunger Halpern of the US National Institute of Standards and Technology (NIST) and the University of Maryland propose a set-up in which an experimentalist sends information back in time to retroactively – in effect – change their actions in a way that produces optimal measurements. Intriguingly, the trio reveal that such simulated time travel in entangled systems can facilitate physical advantages that would be impossible to achieve in purely classical systems.
The science of quantum measurements
While actual backward time travel is hypothetical, quantum mechanical versions have been proposed and simulated experimentally. A crucial ingredient of these simulations is teleportation, wherein a state from the experiment’s intermediate step is effectively sent back to the beginning. For this to be possible, the states must be entangled. In other words, they must share a type of quantum connectedness that arises between two (or more) particles such that the state of one cannot be defined independently of the other(s).Since these simulations of time travel rely on quantum mechanics, they enable researchers to ask meaningful questions about the nature and advantages, if any, of quantum systems. In the new work, Arvidsson-Shukur, McConnell and Yunger Halpern do just that by investigating what advantages simulations of backward time travel can have for quantum metrology – a field of physics that uses quantum mechanics to make highly precise measurements. Full Article @ Physicsworld
Physicists Say Time Travel Can Be Simulated Using Quantum Entanglement
Isaac Schultz - Gizmodo
The quantum world operates by different rules than the classical one we buzz around in, allowing the fantastical to the bizarrely normal. Physicists have described using quantum entanglement to simulate a closed timelike curve—in layman’s terms, time travel.
Before we proceed, I’ll stress that no quantum particles went back in time. The recent research was a Gedankenexperiment, a term popularized by Einstein to describe conceptual studies conducted in lieu of real tests—a useful thing when one is testing physics at its limits, like particles moving at the speed of light. But a proposed simulation involves “effective time travel,” according to the team’s recent paper in Physical Review Letters, thanks to a famously strange way that quantum particles can interact.
That interaction is called quantum entanglement, and it describes when the characteristics of two or more quantum particles are defined by each other. This means that knowing the properties of one entangled particle gives you information about the other, regardless of the distance between the two particles; their entanglement is on a quantum level, so a little thing like their physical distance has no bearing on the relationship. Space is big and time is relative, so a change to a quantum particle on Earth that’s entangled with a particle near a black hole 10 billion light-years away would mean changing the behavior of something in the distant past.... Read More
Quantum time travel: The experiment to 'send a particle into the past'
Time loops have long been the stuff of science fiction. Now, using the rules of quantum mechanics, we have a way to effectively transport a particle back in time – here’s how
When Seth Lloyd first published his ideas about quantum time loops, he hadn’t considered all the consequences. For one thing, he hadn’t anticipated the countless emails he would get from would-be time travellers asking for his help. If he could have his time over again, he jokes, he “probably wouldn’t have done it”.
Sadly, Lloyd, a physicist at the Massachusetts Institute of Technology, won’t be revisiting years gone by. Spoiler alert: no one will go back in time during the course of this article. But particles? That is another matter.
Theoretical routes to the past called time loops have long been hypothesised by physicists. But because they are plagued by impracticalities and paradoxes, they have been dismissed as impossible for just as long. But now Lloyd and other physicists have begun to show that in the quantum realm, these loops to the past are not only possible, but even experimentally feasible. In other words, we will soon effectively try to send a particle back in time. ... Read More
Quantum Entanglement Mind Over Matter Consciousness effects the Physical World
Quantum entanglement is a phenomena whereby two subatomic particles are 'entangled' and ones actions will influence the others instantaneously, regardless of the distance between the two. Taking quantum entanglement a step further there lies a truly bizarre supposition of quantum theory that states the very act of observing affects the observed reality. It's mind over matter squared. Some unknown force linked to consciousness seems to have af effect on subatomic particles. ... Read More
Simulations of ‘backwards time travel’ can improve scientific experiments
Researchers at the University of Cambridge have shown that by manipulating entanglement – a feature of quantum theory that causes particles to be intrinsically linked – they can simulate what could happen if one could travel backwards in time. So that gamblers, investors and quantum experimentalists could, in some cases, retroactively change their past actions and improve their outcomes in the present. Cambridge University October 2023 .. Full Article